1. Field of the Invention
The present invention relates to an image retrieving device for classifying and retrieving a digital image, a method for adding keywords in the image retrieving device, and a computer program therefor. In particular, the present invention relates to an image retrieving device for classifying and retrieving a digital image, a method for adding keywords in the image retrieving device, and a computer program therefor such that it is possible to add keywords to the image efficiently by detecting an object (for example, a human) in the image during retrieving and classifying the image.
2. Description of Relate Art
Recently, digital cameras are prevailing so popular that it is often that digital images which is formed by taking pictures (hereinafter, called an image for short) is stored in a PC (personal computer) and displayed on a display of the PCs later so as to view for pleasure. Also, it is often that the stored images are clipped out so as to be edit on a display of the PCs and collect them as a photo album electronically.
In such a case, it is necessary to clip out necessary images among numerous images by retrieving the digital images which are stored in the PCs. For an efficient retrieval for the digital images, it is necessary to add anything like keywords to the images which is stored (registered) for a retrieving purpose.
For general cases, an ordinary user of a digital camera takes pictures of humans such as her, or his family. In such a case, it is useful to store the images while adding keywords for specifying the human (object) whose picture is taken.
However, it needs experience and skill as a background for expertise in adding and classifying keywords and retrieving the images efficiently; thus, such categorization and retrieval have been difficult and disturbing for ordinary users.
For such storage and retrieval for the images, several prior arts have been disclosed as follows so as to deal with the above problems.    (1) External information (such as place, date, and contents which are pictured) are added to the images in advance which are supposed to be retrieved; thus, the external information is used for the retrieval.    (2) Also, a product has been released marketwise by which a quantitative characteristics in the image are (such as color and shape) utilized such that the user may retrieve the image efficiently by disposing the object image above a three-dimensional space according to the quantitative characteristics of the image.    (3) Also, there is a prior art for “Method for hierarchically classifying image and device for classifying and retrieving picture and recording medium with program for executing the method recorded thereon” which is disclosed in Japanese Unexamined Patent Application, First Publication No. 2001-160057.
The invention which is disclosed in Japanese Unexamined Patent Application, First Publication No. 2001-160057 relates to a technique in which images are classified and retrieved interactively and hierarchically while using an image dictionary which is produced in advance. In this invention, a system proposes major classifying points such as an area color, a line, an object, and an image dictionary for a group of image to the user during the navigation. When the user selects the image dictionary, the system proposes classifying points such as a “face of a human”, “sky”, and “roof”. When the user selects the “face of human”, the system proposes a group of image for picture of human. Similarly, minor classifying points such as the area color, a liner line, an object and an image dictionary are proposed to the user for a group of the image; thus, a classifying operation is performed by selecting the classifying points. Such a navigation history is useful for classifying the image DB; therefore, the navigation history is saved in the system as a classifying tree information. It is possible to view a general view of the image DB by browsing an entire image of the saved classifying tree by using the keywords and synthesized images.    (4) Also, there is a prior art for “a face image model retrieval processing method” which is disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 8-221547.
An object of the invention which is disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 8-221547 is to provide a simple face image model retrieval processing method in which it is possible to extract characteristics of the face area very accurately and effectively in a high speed from the object as a written datum. Consequently, a face area mosaic characteristics extracting section forms a variable density image which includes the face area in a mosaic manner; thus, the face area is extracted as a face area mosaic characteristics datum by making use of a fact that such a mosaic pattern is different between an inside and the outside of the face area. Next, a face image classification retrieving section retrieves a class in the categorized classification. By doing this, it is possible to extract and retrieve the face area very accurately in high speed not by using an edge section in the object for extracting the face area but by using a density pattern in the object area. Also, it is possible further to classify the categorized classification for the retrieval operation.    (5) Also, there is a prior art for “retrieving keyword determining method, its device, document retrieving device, and recording medium” which is disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 10-307849.
An object of the invention which is disclosed in the Japanese Unexamined Patent Application, First Publication No. Hei 10-307849 is to specify only necessary keywords in a document retrieving device in which it is possible to perform a thesaurus retrieving operation by using a plurality of keywords which relate each other. In addition, in a keyword determining device, nominated keywords which are supposed to be added to the inputted keywords are retrieved from a thesaurus dictionary. Simultaneously, a document for explaining the nominated keywords is retrieved from an explanatory document file. Consequently, a score which corresponds to a relating degree to the inputted keywords and the nominated keywords is added to the explanatory documents; thus, the score is displayed n a display device so as to expedite the user to determine whether or not for adding the nominated keywords. If the user's decision is analyzed, and if it is determined that the keywords are not necessary to be added, only the inputted keywords are used for the retrieving operation.
If it is necessary to add the nominated keywords, such nominated keywords are added for the retrieving operation.
However, the above conventional methods have following problems.
In the method which is explained in the above paragraph (1) for adding the external information to the image, it is necessary to add the external image to all images preferably. However, it is a very disturbing operation to add the external information (keywords) to the image so as to realize a retrieving operation in variable forms; thus, such an operation is not realistic.
In the method which is explained in the above paragraph (2) for using a quantitative characteristics of the image itself, a plurality of images which have equal quantitative characteristics are displayed on the display device according to a certain law so as to extract a desirable image therefrom. Therefore, the object of the invention which is explained in the above paragraph (2) is different from the object (for example, a human) of the present invention for performing an efficient retrieving operation for the objects in the image.
The object in the method in the above paragraph (3) which is disclosed in Japanese Unexamined Patent Application, First Publication No. 2001-160057 is to perform classify and retrieve the image interactively in a hierarchically by using the image dictionary which is produced in advance. The object of the present invention is to add the keywords efficiently by detecting the object (for example, a human) in the image; therefore, the object and the structure in the present invention is different from the object and the structure in the invention which is disclosed in Japanese Unexamined Patent Application, First Publication No. 2001-160057.
The object in the method in the above paragraph (4) which is disclosed in Japanese Unexamined Patent Application, First Publication No. 8-221547 is to categorize the categorized classification by forming a variable density image of the face image. An object for the present invention is to add keywords efficiently by detecting the object (such as a human) in the image; thus the object ant the structure in the invention which is disclosed in Japanese Unexamined Patent Application, First Publication No. 8-221547 are different from those in the present invention.
The object in the method in the above paragraph (5) which is disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 10-307849 is to select the nominated keywords which are supposed to be added to the inputted keywords from the thesaurus dictionary. The object of the present invention is to add the keywords efficiently by detecting the object (such as a human) in the image; thus, thus the object ant the structure in the invention which is disclosed in Japanese Unexamined Patent Application, First Publication No. Hei 10-307949 are different from those in the present invention.